An ultrasonographic apparatus irradiates an ultrasonic wave to the patient by using an ultrasonic probe, measures the acoustic characteristic of a biological tissue within the patient by using the reflection echo signal, re-constructs a form image (such as a B-mode image and an M-mode image) of the biological tissue, for example, based on a difference or change in acoustic characteristic of an arbitrary area of the patient and displays the form image on a screen for a diagnosis.
Recently, it has been proposed that the ultrasonographic apparatus is used to measure elasticity information including either elasticity ratio or elasticity distortion, for example, of a biological tissue of a part to be diagnosed and display it as an elasticity ratio image or elasticity distortion image (each of which will be generally called elasticity image, hereinafter) (in Japanese Unexamined Patent Application Publication No. JP/P2000-60853A, for example). According to this, the form image of the biological tissue of the patient and the elasticity image such as the elasticity ratio and elasticity distortion, for example, are acquired simultaneously or alternately, and the form image and the elasticity image are displayed in line or one over another on one screen.
However, the ultrasonographic apparatus disclosed in the publication does not consider a measurement method for acquiring both high quality form and elasticity images.